Lead salt laser diodes.

Lead chalcogenides are direct semiconductors with small energy gap (ΔE≲0.3 eV) and therefore useful materials for optoelectronic devices in the infrared spectral region. Here we will discuss their use as laser diodes emitting between 2 and 20 μm. The state of crystal growth techniques and diode technology is reviewed in respect to low threshold current densities, high temperature operation in cw and pulsed mode and power output. Tuning of the emitted wavelength by temperature, hydrostatic pressure and magnetic fields is dealt with in detail. The applications of such diodes in gas spectroscopy are summarized. [ABSTRACT FROM AUTHOR]